Use ShaderVars instead of ShaderLang in headers. We only need the typed variable information in our header files. The entry point and other enum info can be encapsulated better in the cpp files that call through to the translator. The only tricky one is the compile options, which we return from our implementation - put the typedef for these in the ShaderVars header to fix this. This should partially work around the problem of shaderlang for Vulkan and ANGLE's translator (also ShaderLang) using some identifiers with the same names. BUG=angleproject:1576 Change-Id: I43c530486498c210796b9e197a6780bf2f7b3afb Reviewed-on: https://chromium-review.googlesource.com/412423 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>